The invention pertains to methods of forming metal-containing films over surfaces of semiconductor substrates. In particular applications, the invention pertains to methods of forming copper-containing films. The copper-containing films can be formed on dielectric materials (such as, for example, silicon dioxide or low-k dielectric materials) or on barrier layers comprising one or more of titanium, tantalum, tungsten and molybdenum; including barrier layers comprising nitride compositions of one or more of titanium, tantalum, tungsten and molybdenum, and barrier layers comprising suicides of one or more of titanium, chromium and cobalt. The invention also pertains to semiconductor constructions. Additionally, the invention pertains to deposition of materials in nanostructures with high aspect ratios on substrates.
It is frequently desired to form metal-containing materials over semiconductor substrates. The metal-containing materials can be incorporated into integrated circuit devices, and/or can be utilized for formation of conductive interconnects between integrated circuit devices.
Copper is a commonly-used conductive material, and is frequently formed over semiconductor substrates for utilization in conductive interconnects. A difficulty in utilizing copper in semiconductor fabrication is that diffusion can occur between copper and various semiconductive materials, including, for example, silicon. Accordingly, barrier layers are often utilized to separate copper from semiconductive materials. Typical barrier layers can include one or more of tungsten, tantalum and titanium. Suitable materials for the barrier layers include, for example, tungsten nitride, tantalum nitride, and/or titanium nitride. Additionally, or alternatively, barrier layers can comprises silicides such as, for example, TiSi2, CoSi2, and chromium silicide.
Although the barrier layers can alleviate or prevent the problem of diffusion between copper and semiconductive materials, the utilization of barrier layers can create new difficulties in semiconductor device fabrication. For instance, it can be difficult to adhere copper to barrier layers.
It is noted that semiconductor processing can comprise formation of metal-containing materials directly on various surfaces without utilizing a barrier layer between the surfaces and the metal-containing materials. For instance, if the metals of the metal-containing materials are so-called noble metals (such as rhodium an iridium, for example), the metal-containing materials can frequently be utilized without barrier layers. Also, if metal-containing materials are deposited on surfaces from which diffusion is unlikely (such as, for example, surfaces comprising Pt or RuO2), barrier layers can be omitted.
It can be desired to incorporate one or more of various metals (such as, for example, copper, platinum, tungsten, rhodium, ruthenium, iridium, gold and nickel) into semiconductor devices. Incorporation of any of the various metals into semiconductor devices can be difficult. It would therefore be desirable to develop new methods for incorporating metal-containing materials into semiconductor constructions.
In one aspect, the invention encompasses a method of forming a metal-containing film over a surface of a semiconductor substrate. The surface is exposed to a supercritical fluid. The supercritical fluid has H2, at least one H2-activating catalyst, and at least one metal-containing precursor dispersed therein. A metal-containing film is formed across the surface of the semiconductor substrate from metal of the at least one metal-containing precursor.
In one aspect, the invention encompasses a method of forming a metal-containing film over a surface of a semiconductor substrate wherein the surface is exposed to a supercritical fluid having H2, at least one H2-activating catalyst, and at least one metal-containing precursor dispersed therein. The metal-containing film has from greater than 0 atom % to less than or equal to 5 atom % of the catalyst incorporated therein together with metal from the metal-containing precursor.
In one aspect, the invention encompasses a method wherein a copper-containing film is formed over and physically against a barrier layer comprising one or more of tungsten, tantalum, cobalt, chromium and titanium, such as, for example, a layer comprising nitrides and/or suicides of one or more of tungsten, tantalum, cobalt, chromium and titanium. The film is formed by exposing a surface of the barrier layer to a supercritical fluid having a copper-containing precursor, a palladium catalyst, and H2 dispersed therein. The film consists essentially of copper and palladium, with the palladium being present to a concentration of greater than zero atom percent and less than 5 atom percent, such as, for example, less than 0.2 atom percent.
In one aspect, the invention encompasses a semiconductor construction having a layer of metal across a surface of a semiconductor substrate. The layer consists essentially of a first metal and a second metal. The first metal is selected from the group consisting of Al, Au, Co, Cr, Cu, Hf, In, Ir, Mo, Ni, Rh, Ru, Sn, Ta, Ti, W, Zr and mixtures thereof; and the second metal is selected from the group consisting of palladium, platinum, rhodium, iridium, ruthenium and mixtures thereof. The second metal is different than the first metal, and the layer comprises at least 95 atom percent of the first metal.